package cn.lcsjsxy.yxc.io;

import org.junit.jupiter.api.Test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Scanner;

/**
 * 测试FileInputStream和FileOutputStream的使用
 * <p>
 * 结论：
 * 1.对于文本文件（.txt,.java,.c,.cpp）,使用字符流处理
 * 2.对于非文本文件(.jpg,.mp3,.mp4,.avi,.doc,.ppt,....)，使用字节流处理
 */

public class FileInputOutputStreamTest {

    //使用字节流FileInputStream处理文本文件，可能出现乱码
    @Test
    public void testFileInputStream() {
        FileInputStream fis = null;

        try {
            //1.造文件
            File file = new File("hello.txt");

            //2.造流
            fis = new FileInputStream(file);

            //3.读数据
            byte[] buffer = new byte[5];
            int len;  //记录每次读取的字节的个数

            while ((len = fis.read(buffer)) != -1) {
                String str = new String(buffer, 0, len);
                System.out.print(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            try {
                if (fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /*
     * 实现对图片的复制操做
     * */
    @Test
    public void testFileInputOutputStream() {
        FileInputStream fis = null;
        FileOutputStream fos = null;

        try {
            //1.
            File srcFile = new File("婉茗.jpg");
            File destFile = new File("婉茗1.jpg");

            //2.
            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);

            //3.复制过程
            byte[] bytes = new byte[5];
            int len;
            while ((len = fis.read(bytes)) != -1) {
                fos.write(bytes, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            try {
                if (fis != null)
                    fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

            try {
                if (fos != null)
                        fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    //指定路径下文件的复制
    public void copyFile(String srcPath,String destPath){
        FileInputStream fis = null;
        FileOutputStream fos = null;

        try {
            //1.
            File srcFile = new File(srcPath);
            File destFile = new File(destPath);

            //2.
            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);

            //3.复制过程
            byte[] bytes = new byte[1024];
            int len;
            while ((len = fis.read(bytes)) != -1) {
                fos.write(bytes, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //4.关闭资源
            try {
                if (fis != null)
                    fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

            try {
                if (fos != null)
                    fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Test
    public void testCopyFile(){
        Scanner scanner=new Scanner(System.in);
        System.out.print("请输入原文件名：");
        String srcPath=scanner.nextLine();
        System.out.print("请输入copy文件名：");
        String destPath=scanner.nextLine();

        long start=System.currentTimeMillis();

        copyFile(srcPath,destPath);

        long end=System.currentTimeMillis();

        System.out.println("复制操做花费的时间为："+(end-start));
    }

}
